运行状态下海上风机结构振源特性研究

Vibration source features of offshore wind power structures under operational conditions

由于海上风机结构运行环境的复杂性,其振源的准确识别与振源特性研究已经成为风机运行安全性评估的重点问题。以某新型复合式筒型基础结构海上风力发电试验样机为研究对象,依据原型观测获得的全负荷条件下结构不同位置的振动响应数据,对不同运行工况下诱发结构振动的振源进行全面识别与分析。利用谱峭度法识别明确引起海上风机结构振动的主要振源及其对应振动响应的频域属性,通过经验模态分解法对实测信号进行分解得到表征各振源特性的频域或频率尺度的分量,同时引入振动能量法对不同振源的能量比重进行统计分析,给出了海上风机结构运行状态下结构整体振动主振源及其对应振动能量分布随运行因素变化的分布规律。研究表明随着机组负荷的增加运行状态下海上风机结构振动的振源变化遵循由单一的环境荷载激励转为环境荷载激励和叶轮转动联合作用再到完全由叶轮转动产生的谐波激励影响的规律。

Due to the operational environment complexity of offshore wind power structures, the correct identification of their vibration sources and their vibration source features study become key problems for their operation security assessments. Here,a new type test prototype of offshore wind turbine with a composite cylindrical foundation structure was taken as the study object,according to vibration response data at the structure＇s different positions measured on the original prototype under the condition of full loading,its vibration sources to excite structural vibrations under different operational conditions were identified and analyzed. Firstly,the main vibration sources causing structural vibrations of the offshore wind turbine,and frequency domain properties of the corresponding vibration responses were identified with the spectral kurtosis（ SK） method. Secondly,the measured signals were decomposed using the empirical mode decomposition（ EMD） method to obtain components in frequency domain or frequency scale characterizing different vibration sources＇ features. Simultaneously,the vibration energy method was introduced to analyze statistically energy proportions of various vibration sources. At last,the distribution laws of the main vibration sources of the offshore wind turbine＇s entire structure under operation and the relevant vibration energy with the variation of operational factors were derived. The study showed that the vibration sources of the offshore wind turbine under operation have a variation law from pure environmental load excitations to the combination of ambient loads and its impeller rotating,and finally to harmonic component excitations caused by its impeller rotating.